The use of electronic medical records (EMRs) in ambulatory settings is widely recommended to improve the safety, quality and efficiency of patient care. Most research demonstrating the efficacy of EMRs comes from four exemplar institutions that have system level resources and support for financial, educational and information technology not commonly available in community practice settings. Less, however, is known about the effectiveness of EMRs for care improvement in community ambulatory settings where most primary care in the United States is delivered. Objective: Our principal research question is: How are EMRs used among community-based primary care practices to care for patients and how are use patterns related to health care quality? To address this question, three aims will be accomplished: Aim 1: To describe how EMRs are generally used in a broad range of clinical care and non-clinical activities;Aim 2: To describe how EMRs are specifically used in acute and chronic care clinical processes;and Aim 3: To identify strategies that guide EMR use in community-based primary care practices. Methods: This study involves collection of multi-method data (observation, interview, survey) and employs a qualitative research methodology. Study participants will be practice members at physician-owned, single specialty community primary care practices that use an EMR and participated in our ULTRA study (N=16). Practice selection will be purposeful and iterative. The first two practices will be randomly selected, and in depth qualitative data will be collected. At the same time, an EMR survey will be completed by members of all participating practices. Data from this survey will inform subsequent practice selection. The survey includes items about EMR use and system functionality, and items to evaluate human factors that shape information system use. EMR survey responses and qualitative data from the first two practices will be analyzed, and insights will inform the selection of the next two practices for in depth data collection and analysis. Practices will be selected that offer the opportunity to maximize variation and learning. The iterative process of purposefully selecting practices and collecting and analyzing data to identify the important determinants of EMR use will continue until saturation is reached - the point at which new cases provide no new information related to EMR use. We anticipate this will occur after studying 8 practices. At this point, two additional practices will be selected to confirm/disconfirm findings. Data Analysis: With the assistance of national experts, a comparative analysis will be conducted using a series of immersion/crystallization cycles to develop a comprehensive understanding of EMR use and the organization of care in community primary care practice. Benefits: This study will identify how community primary care practices use EMRs to support clinical and non-clinical care processes. Findings will be used to generate hypotheses about effective EMR use to be tested in a subsequent R01 among a representative sample of practices. This work paves the way for interventions to improve clinical care through more effective EMR use. Public Health Relevance: This study will be an important contribution, extending current knowledge of how EMRs are used to support clinical and non-clinical care processes in community-based primary care practices. This innovative study is the first step in a program of research to improve clinical care through more effective EMR use in this setting.